1. Field of the Invention
The present invention relates to a printing method and apparatus therefor, and more particularly, to a printing method and apparatus where the image is recorded without leaving margins in the leading and trailing edges of a sheet of printing paper.
2. Description of the Related Art
In general, a thermal transfer printer includes a thermal record head having a predetermined heating device and an ink-deposited ribbon. The ribbon is located between a printing paper and the thermal print head. Thus, the ink can be sublimated in a predetermined pattern by a thermal print head and thus transferred onto the printing paper. A color thermal transfer printer superposingly performs printing three times in order to print a color-separated yellow, magenta and cyan image.
FIG.1 illustrates a conventional thermal transfer printer. A cassette 6 for receiving a printing paper 4 is provided below a drum 2. A guide roller 3 for guiding printing paper 4 supplied from cassette 6 while pressing the paper onto drum 2 is installed on the circumferential surface of drum 2. A clamp 5 for clamping the leading edge of printing paper 4 and rotating together with drum 2 is installed onto a drum shaft 2'. A thermal print head 1 heated by a predetermined heating element is installed above drum 2 to be movable up and down.
Meanwhile, an ink ribbon 7 is provided between thermal print head 1 and printing paper 4. Thermal print head 1 is heated in accordance with a predetermined printing signal, and at the same time, applies pressure to ink ribbon 7 so that ink can be sublimated in a known manner. Thus, an image is printed onto printing paper 4.
In the conventional thermal transfer printer, printing is performed by the following method. First, printing paper 4 is supplied from cassette 6 toward drum 2 and clamped by clamp 5 at the leading edge thereof. Then, clamp 5 and drum 2 rotate together so that the leading edge of printing paper 4 can be located to the point beyond the initial printing location of thermal print head 1 as shown in FIG.1. Of course, if clamp 5 is located at the initial printing location (a central portion under the thermal print head), clamp 5 would interfere with the operation of print head 1 when the print head descends for performing a printing operation. Then, thermal print head 1 descends in order to press/heat ink ribbon 7. Thus, ink is sublimated so that an image is printed.
However, in the conventional thermal transfer printer, since printing paper 4 is transmitted in the state where the leading edge of printing paper 4 is clamped by clamp 5, the leading edge of printing paper 4 is not printed on.
Therefore, as shown in FIG. 10, a margin is made around the printed image, specifically in the leading edge of printing paper 4, which results in a poor appearance.